Thomas Graham

Graham, Thomas, 1805–69, Scottish chemist, best known for research in diffusion in both gases and liquids that led to his formulation of Graham's law. His discovery that certain substances (e.g., glue, gelatin, starch) pass through a membrane more slowly than others (inorganic salts, e.g., common salt, or sodium chloride) led him to draw a distinction between the two groups, calling the former (the slower) colloids and the latter crystalloids. In this connection he discovered dialysis. His work was the earliest in colloidal chemistry. His investigation of phosphoric acid led to the present chemical concept of polybasic acids.